1. Field of the Invention
The present invention relates to a heat exchanger for improving heat exchanger effectiveness between fluid of high temperature and that of low temperature and enhancing compactness thereof.
2. Description of Related Art
Various heat exchangers of this type are known so far. For example, firstly a multitube type heat exchanger having bundle of tubes disposed inside a cylindrical vessel for performing heat exchange by flowing two fluids in each tube and the cylindrical vessel, secondly a coil type heat exchanger having a coil formed of a helically winding tube or a spiral tube or many straight pipes coupled by curved pipes and disposed and soaked inside a vessel for performing heat exchange between two fluids inside the tube and vessel, thirdly a spiral type heat exchanger having two parallel fiat plates which are wound helically and disposed inside an airtight cylinder for performing heat exchange between two fluids while swirling two fluids, fourthly a plate type heat exchanger having thin corrugated plates which are laid one on the other and fastened so as to permit two fluids to flow alternately to chambers defined between spaces of corrugated plates, and fifthly a fin tube type heat exchanger having fins on an outer wall of a circular pipe.
However, in either of the heat exchangers, heat exchange can be performed between the pipe, plates or fins and surface layer of the flowing fluid, and hence the fluid has no irregularity in its temperature distribution during the flowing thereof and quantity of fluid which does not contact the heat transfer surface is larger so that thermal efficiency is deteriorated. Further, since the thermal conductivity is determined by a heat transfer area of mere pipes, corrugated plates, fins, such heat exchangers has drawbacks in that number of pipes is increased and the corrugated plates are enlarged for enhancing the thermal conductivity for enhancing thermal efficiency.